The Human Performance and Functional Testing Core is designed as both a service core and a development core. It will provide accurate and reliable research acquisition and processing services, specifically for projects #1 and #2 of the TOQIO CORT, as well as for other research teams at UCSF. It is also committed to the development of innovative monitoring of physical activity in persons with OA to evaluate the contribution of loading behaviors to cartilage health and disease. The Core will also serve as a valuable resource for multi-disciplinary pilot projects that emerge as part of the CORT mechanism. The overall objective of the Human Performance and Functional Testing Core is to provide comprehensive state-of- the-art three-dimensional motion analysis and functional testing facilities for experimental research projects and to develop new methods with improved technical capabilities. The Core is equipped with high-resolution motion analysis capabilities, including a 10-camera VICON optical motion capture system with capture frequency capabilities up to 1000 HZ and a cluster-based retro reflective marker set, 2 AMTI force platforms, and 2 high-resolution high-speed digital video cameras. The Core personnel are experts in the fields of motion analysis, sports medicine, and functional testing. The core will provide for accurate and reliable motion analysis acquisition and processing, as well as provide training and facilities for physical performance and functional testing procedures. Finally, the Core will provide resources for biosensor development for osteoarthritis (OA) research and personnel with extensive expertise in wireless sensor development and fabrication. The Core is ideally positioned with close access for all researchers and patients using this resource. The Core will be housed in the Human Performance Center on the Mission Bay Campus. This facility is a 900 square-foot laboratory located in the newly built Orthopaedic Institute at UCSF. Clinical recruitment will primarily be performed through orthopaedic clinics, which take place on the second floor of the Orthopaedic Institute., All Principle Investigators utilizing this Core have offices nearby, on or around the Mission Bay campus. Imaging facilities are also located in very close proximity to the Core, minimizing subject inconvenience, and facilitating ease of referral and data acquisition.